When these three toddlers were babies, they hit developmental markers on a wide range of "average." Of course, if your baby isn't hitting milestones as early as your friend's child, or your firstborn, it's easy to get a bit anxious. Relax: Here's proof that kids develop at their own pace.

Ethan19 months, Castaic, CAAlready a big sports fan, Ethan can't get enough football on TV or baseball on Wii.

Mayli
24 months, St. Paul, MNMayli enjoys going on the swings at the park -- but only if she can go really high!

Sam 27 months, Huntersville, NCHe's a fan of Thomas the Tank Engine and was giving his parents high fives by age 1.

Average age: 5 to 8 weeks

"During a shopping trip, I was running down the aisles with Sam in his car seat in the cart. For the first time, he looked right at me and smiled. It seemed like he was enjoying himself, so I kept at it!"-- Leslie Netta, Sam's mom

Though a 1-week-old may give you a gas grin, you may not see a social smile -- where your baby reacts to your facial expressions while maintaining eye contact -- until he's 2 months old. "Smile and coo at him while giving a bath, dressing, or changing him, and a true smile will come naturally," says Alice Sterling Honig, Ph.D., professor emerita of child development at Syracuse University in New York.

Average age: 3 to 4 months

"First, Mayli grabbed my hair! Then we found a lightweight rattle
to encourage her new skill -- and she never wanted to let go of it!"-- Cassi Willoughby, Mayli's mom

When your child reaches for an object, put it in her palm, hold it still, and let her grab for it. She still gets the sensation of touching different textures even if the object falls out. "Use a feather, a blanket, your finger, whatever," says Tanya Remer Altmann, M.D., a pediatrician and editor-in-chief of the American Academy of Pediatrics's book The Wonder Years. "They're learning from every little thing!"

Average age: 6 to 7 months

"My first child, Parker, sat up by five months, so I was worried when Mayli couldn't do it at the same age. She was wobbly at first, but eventually she got it. I stopped comparing my kids after this." -- Cassi Willoughby

"If your baby can hold up her head and push herself up from her tummy with her arms, she's probably ready to try sitting up," says Paula Jackson, a certified nurse-practitioner in Philadelphia who specializes in early childcare and safety. You can prop her up with pillows on the floor at 4 months (stay close by!) or have her lean forward with her legs apart, supporting herself with her hands. That'll help her learn to balance.

Average age: 8 to 9 months

"Mayli was feeding herself crackers at six months and using a spoon by the time she was a year old. Once she figured out she could do it herself, she didn't want me to feed her anymore." -- Cassi Willoughby

Once your baby's on solids, she can try feeding herself under your supervision while she's seated. (She can choke if she's moving around.) Offer small chunks of finger foods, like ripe bananas, chicken, or cereal. When you feed her, she may start grabbing the spoon. Most kids can't use utensils until they're 15 to 18 months old, so have one spoon to feed her with and another for her to play with.

Average age: 8 to 10 months

"I would always sing Sam songs with his name in them, but I couldn't tell if he understood he was Sam. One day, he turned around to look at me when I sang his name, and then I knew."
-- Leslie Netta

If your 8-month-old isn't turning to the sound of his name, try cutting out background noise (TV and music can drown out your voice) and giving him plenty of time to respond. Say his name clearly and loudly, and wait until he stops what he's doing and refocuses his attention on you before you say anything else, says Dr. Altmann.

Average age: 8 to 10 months

"My friend's son walked at a little over ten months, so I was nervous that Ethan still wasn't even crawling. Then he started, but he crawled backward! And he'd only do it while dragging his toy truck along."-- Top Nguyen, Ethan's mom

Many kids skip crawling, but the ones who do it may start without warning -- and it may not look quite like what you expected. Babies may scoot on their bottoms, slither on their tummies, or just roll around. If you have hard flooring throughout your home, lay down some interlocking foam tiles so your child has a more comfortable crawling surface, suggests Dr. Altmann.

Average age: 9 to 11 months

"Mayli would use furniture and other people to get wherever she wanted to go. Even though she couldn't yet stand on her own, she always found a way to move around!" -- Cassi Willoughby

Once your baby's cruising, put some sturdy, stable pieces of furniture -- like low tables and heavy chairs -- close together so that she's motivated to get around by using her feet instead of by crawling.

Average age: 10 to 12 months

"By three and a half months, Sam was trying to stand in my lap, and at seven months, he could stand on the floor while holding on to furniture. But it took him five months to let go! He likes to take his time." -- Leslie Netta

Put toys on a low table to encourage your child to pull himself up to reach them. He'll hold on to the table for support, but the toys will prompt him to let go a little. Or try holding a toy a little bit away from him so he reaches for it. Just be ready to catch him if he falls!

Average age: 12 to 13 months

"At four months, Ethan babbled dramatically with hand motions, like he was telling a story, but that first real word didn't come for five more months. He still babbles a lot, but we understand more of what he says now." -- Top Nguyen

"Mama" and "dada" are the most common first words, but some kids say "baba" (for bottle or ball) or the name of their sibling or pet first. "It's usually whatever word kids hear the most or need to say to get your attention," says Dr. Altmann. At around 18 months, they'll say entire words("mommy," "daddy," "bottle") instead of repeating the first syllable ("mama," "dada," "baba"), and they'll even start saying two-word phrases.

Average age: 12 to 15 months

"At the fourteen-month mark, we were really concerned and about to take Ethan to the doctor. Then, one night, we put him on the floor and he took nine steps. Later that night, he even made a U-turn!" -- Top Nguyen

Walking takes tons of confidence -- build your baby's by taking steps with him while holding his hands. Then switch to offering him only one hand to hold. Finally, use a single finger as a guide when you think he's almost got it. Try dancing together, too -- it's a fun way to get him comfortable with moving on his feet. But also: Don't worry. He'll walk when he's ready!